


Betrayal

by DancingInTheSliverGlow



Series: Febuwhump 2021 [20]
Category: Shadowhunters (TV)
Genre: Alec Lightwood Deserves Nice Things, Alec Lightwood Loves Magnus Bane, Angst, Angst with a Happy Ending, BAMF Magnus Bane, Betrayal, Blood, Downworlders, Emotional Hurt/Comfort, Established Relationship, FebuWhump2021, Febuwhump, Gen, Hurt Alec, Hurt Alec Lightwood, Hurt Magnus Bane, Hurt/Comfort, Love, M/M, Magic, Magnus Bane Deserves Nice Things, One Shot, Powerful Magnus Bane, Protective Magnus Bane, Rituals, Runes, Short One Shot, Spells & Enchantments, Tumblr, Warlock Magnus Bane, Warlocks
Language: English
Status: Completed
Published: 2021-02-21
Updated: 2021-02-21
Packaged: 2021-03-18 13:22:34
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,335
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29610072
Author URL: https://archiveofourown.org/users/DancingInTheSliverGlow/pseuds/DancingInTheSliverGlow
Summary: A mysterious illness is taking downworlder children's lives. Magnus finds a ritual to get rid of the illness, but the trick is that it requires nephilim blood. Magnus grew up with nephilim. He knows, more than anyone else, how fiercely Nephilim guard their blood.Nephilim are taught from the moment they can speak to never, ever allow a warlock, or any downworlder for that matter, access to their blood. A warlock’s power is in their core, where they can use it and manipulate it, but nephilim don’t have magical cores - their power is located in their blood. The use of that blood in a potion or ritual gives the warlock absolute and total power over the Shadowhunter in question - not just over their body and what happens to it, harm, injury or otherwise, but power over their minds and hearts as well. Anything the warlock wants to do to them, they can, easily.It is the nephilim culture’s highest taboo and the punishment for a warlock caught doing, so is the most brutal and ruthless torture the Clave could imagine when they wrote the laws (and they were very very imaginative).I used Laws and Selene Dreamwalker's prompts word or word from on the Malec Discord, so a huge credit to them!!
Relationships: Alec Lightwood & Catarina Loss, Magnus Bane & Catarina Loss, Magnus Bane/Alec Lightwood
Series: Febuwhump 2021 [20]
Series URL: https://archiveofourown.org/series/2137995
Comments: 10
Kudos: 176
Collections: febuwhump 2021





	Betrayal

**Author's Note:**

> A huge shout out to Laws and Selene Dreamwalker on the Malec Discord. They made this wonderful prompt, and I couldn't resist turning it into a fanfic (with permission from them). There are several instances where I used their prompts, word for word. The summary was Laws's original prompt.

Magnus shuts the spell book and tries, very hard not to scream, or react otherwise. Alec is in the other room, going over modern spell books and he _can’t_ find out about this ritual. If he does, all will be lost and the downworlder children will die.

For several weeks, downworlder children have been coming down with a mysterious sickness. More and more children have been getting sick, and nothing Magnus or any of the Warlock Healers do is helping. They have no idea what’s happening, but it's growing exponentially worse, far too quickly. Last week, several of the infected children had become bedridden, too weak and dizzy to stay upright. Two days ago, the deaths had started.

The entire downworld was frantic. Magnus had widened his search and poured over new and old texts alike, desperate to find any solution, anything that might give these children a chance. 

Eventually he found something, in an ancient cleansing book. The ritual was designed to be a last resort, something to use if all other detection, healing and purifying spells didn’t work. Once performed, ritual would hunt down any and all ailments that plagued the sick within the city and immediately remove them from the body, without further injury. 

It was perfect, aside from two small ingredients that explained why it was a last resort.

7 drops of nephilim blood willingly given,* 

7 drops of nephilim blood forcibly taken.**

_*The blood must be given unknowingly. The reason for the ritual cannot be explained beforehand._

_**All 14 drops of blood must be taken from the same nephilim._

Magnus grew up with Shadowhunters and Nephilim. He knows, more than anyone else, how fiercely Nephilim guard their blood. Nephilim are taught from the moment they can speak to never, _ever_ allow a warlock, or any downworlder for that matter, access to their blood. A warlock’s power is in their core, where they can use it and manipulate it, but nephilim don’t _have_ magical cores - their power is located in their blood. 

The use of that blood in a potion or ritual gives the warlock _absolute_ and _total_ power over the Shadowhunter in question - not just over their body and what happens to it, harm, injury or otherwise, but power over their minds and hearts as well. Anything the warlock wants to do to them, they can, easily. It is the nephilim culture’s highest taboo and the punishment for a warlock caught doing so is the most brutal and ruthless torture the Clave could imagine when they wrote the laws (and they were very _very_ imaginative).

Magnus knows that if he performs this ritual, his life is as good as over. The most he can hope for, is a swift death. Magnus also knows that if he doesn’t perform this ritual, the downworlder children will die, and Magnus won’t be able to live with himself, knowing that he could’ve done something about it. 

In the end, it's an easy decision. Magnus will perform this ritual. 

Of course, there is another possibility; Magnus could hand the ritual off to the Warlock Healers, but Magnus knows that they wouldn’t be able to get the Nephilim blood. In fact, Magnus is the only Warlock that is in any position that has any chance at acquiring 7 drops of nephilim blood _willingly given._

Magnus and Alec have been married for several months. To the Shadow World’s disbelief, Magnus and Alec have grown to trust each other. Magnus knows the other shadowhunters are fearful on Alec’s part. They worry about him, living in close quarters with a _Warlock_ , of all downworlders. Magnus has promised time after time that he would _never_ abuse Alec’s trust like that, and each time Alec has reassured him that _yes_ , he knows Magnus would _never_ do such a thing, and _yes_ , he _trusts_ Magnus.

Magnus allows himself a moment to grieve for their relationship, for the life they could’ve had together. Because after this ritual - _if_ Alec even gives Magnus seven drops of blood and _if_ Magnus is able to overpower the shadowhunter, the moment it’s over, Magnus will no doubtedly be sent to the Clave for punishment, and Alec will want nothing to do with him. 

His life for the children. It’s worth it. 

Magnus inhales, and exhales slowly. He clears his mind, using an old meditation technique. If Magnus is going to pull this off, he can’t let his emotions get the better of him. He glances at himself in the mirror, and does a double take. His eyes are blotchy, and there are tears running down the side of his face. Magnus stares at himself for a moment, and then uses a bit of magic to dry his eyes, clean his face and reapply the make-up. For this to work, Alec can’t suspect _anything._

Magnus grabs the other ingredients, mur, frankincense, dragon’s bone, a bowl, several candles and some chalk and gets to work setting up the ritual. Half an hour later, he’s ready. He opens the door, and calls for Alec.

“Alec, could you help me with a ritual?” 

Alec, of course agrees without thinking. He’s served as a placeholder in several rituals before, it was never a big deal. At least, not until today. 

Magnus starts the ritual, making sure that the book is held in such an angle that Alec can’t see the text. Magnus highly doubts that Alec would be able to read it - the Warlock who had written the text millenia ago had used an old demonic language, but Alec was always full of surprises.

Not to mention, Magnus is pretty sure that the Shadowhunter’s _rune of tongues_ would allow him to read demonic languages.

Out of the corner of his eye, Magnus watches Alec smile as Magnus’s magic swirls around them. Alec has always welcomed Magnus’s magic. Unlike other shadowhunters, or even other downworlders, he doesn’t just accept it. No, he admires it, a childlike wonder on his face whenever it swirls near him. After years of oppression and fear, Magnus found it refreshing. Now, there’s a faint sense of sickness in his gut. Alec trusts him, and trusts his magic. He won’t even see it coming.

Normally, his magic is cool blue, but with the upcoming betrayal and the downworld children at risk, it changed colour. Magnus is just relieved that it turned white-ish blue instead of the usual red when he’s upset. He knows Alec would’ve asked about such a drastic change - Magnus has always welcomed and encouraged Alec to ask about the non-human side of him - and Magnus doesn’t think he has the ability to lie well enough to appease Alec right now.

The ritual goes as planned, not that Magnus had any doubt that it wouldn’t in the first part. The time comes for Magnus to add the nephilim blood, and Magnus sets the book down and picks up a small dagger, the edges honed into lethal sharpness and locks gazes with Alec, feeling far too shaky and pale for his own liking. 

He holds out the dagger and quietly asks for seven drops of blood.

Magnus can pinpoint the exact moment Alec understands what Magnus is asking. As soon as it registers, Magnus practically sees Alec visibly pale and while that’s concerning enough on its own, his other reactions were much more worrying. 

Magnus didn’t consider the possibility that Alec would not only refuse, but also arrest Magnus (merely asking for Nephilim blood was like asking to be locked up for life; Nephilim blood was _that_ well protected) or even physically defend himself.

Magnus has no problem confronting angry nephilim. He’s done that plenty of times in the past, even with his own husband. To some very satisfying ends, in the latter case.

On the other hand, confronting the _terrified_ nephilim who’s face had gone blank and was reaching for his seraph blade? Ha, no.

Magnus had never done that before, because by large nephilim simply didn’t do terror around Downworlders. Afraid? Very occasionally, sure, it was a natural reaction when confronted with danger. But unlike most beings, Shadowhunters had a way of… _training_ the fear out of themselves. After all, they grew up to be warriors, growing ever more terrifying by the day. 

“It’s just you, right?” Alec abruptly asks, in a surprisingly steady voice.

Magnus blinks, startled out of his thoughts and forcing himself not to flinch from his previously terrified husband who… was taking his hand away from his seraph blade, Slowly and with effort but nonetheless moving away from the weapon all the same. “What?”

“It’s just you who will be using my blood. Correct? No one else, nothing else, whatever this is?” Alec gestures to the chalk and candle lit circle they were standing on.

Unsure why Alec is asking this of all things, now of all times, Magnus answers, audibly confused even to himself. “Yes, it’s just me, just for this ritual.” And because he can’t help pushing, he asks, “Alexander, wh-”

“Alright.” Alex states, cutting Magnus off and holds his hand out.

_Holds his hand out._

What.

Magnus doesn’t move. His body isn’t really responding, and he feels somewhat numb, actually. He knew that there was a slim chance that Alec would give him the blood, but he had assumed that he could have to convince and plead with Alec.

This obvious, wholehearted trust, breaks Magnus’s heart knowing what he needs to do afterward.

The magic of the ritual shifts around them, awakening and strengthening, now that it can sense that the nephilim is willing. It knows the blood comes next. 

Magnus only manages a faint, “Alexander?”

Alec, beautiful, lovely Alec, only smiles at him, warm, for all he’s trembling. “I’ve said it before Magnus. I trust you. As long as it’s you, it’s alright.”

 _‘Slowly,’_ Magnus pushes soothingly at the magic of the ritual, which is becoming more bloodthirsty by the second. Magnus can feel it itching and clawing at his skin, grasping for blood, for power. _‘Slowly, the nephilim has agreed, but he’s scared. Slowly.”_

The ritual temporarily calms, and Magnus is reminded of one time, centuries ago when he stood beneath a class 2 hurricane. He feels like he’s back in the center of the eye, and in any given moment the hurricane will move and Magnus will be blasted with the highest, strongest, most destructive winds.

Magnus forces himself steady while he slowly reaches for the nephilim’s, no Alec’s- _his husband’s, he must keep that in mind, must be gentle, because Alec is still hesitant, still scared -_ outstretched, shaking hand with the sharp dagger in his own. 

Seven drops of blood. Such a small thing, containing so much power. 

Magnus slices the tip of Alec’s finger, and surprisingly, Alec doesn’t flinch. Magnus gently squeezes Alec’s finger, and watches as the blood rolls down the side, off his finger and into the magic of the ritual that grows ever increasingly red and bloodthirsty with each drop. 

Magnus feels Alec’s eyes on his hands - on their hands, and they silently count the drops of blood together, as they land in the ritual magic below. Although, Magnus supposes, considering the strength and power growing in the ritual, Magnus doesn’t need to count the blood drops. By seven drops, the magic will be strong enough to take Alec itself, and _forcibly get those seven unwilling drops of nephilim blood_. 

Unlike the magic, Magnus cares about Alec. He cares about what state Alec will be in after this ritual - regardless of what will inevitably happen to himself. Magnus knows that if he lets the ritual magic take the blood, Alec will feel violated, and that feeling will stay with him, and haunt him for the rest of his life.

Magnus grits his teeth and pushes the ritual magic back. _No_ , he tells it, _back off._ Magnus will be the one to get those 7 forcibly taken drops of nephilim blood. Maybe then, there’s a chance Alec won’t be haunted by this for the rest of his life. 

They watch as the seventh drop of blood falls. The moment it lands on the magic, Alec tugs his hand back, but Magnus tightens his grip. Alec shoots him an alarmed look, but Magnus looks away. He can’t bear to look in Alec’s eyes and see the betrayal.

Magnus yanks Alec’s arm, sending Alec stumbling in front of him. Making use of Alec’s shock, Magnus uses his leg to trip Alec lightning fast, and the shadowhunter falls face down onto the floor. Magnus lands on Alec, one arm pinned behind Alec’s back, and a knee pressing weight on Alec’s back. Alec had taught him this move. Magnus executes it perfectly, the whole thing barely taking a few seconds.

Around them, the ritual magic rises and intensifies, hungry, bloodthirsty and sensing more deliciously powerful nephilim blood on the way. Magnus mentally snarls, beating it back, telling it to wait. 

Magnus slashes the side of Alec’s hand using the dagger. Seven drops of blood quickly fall out, into the ritual magic. The instant that the seven leaves Alec’s hand, Magnus uses his magic to heal the wound. 

The ritual magic becomes almost immeasurably more intense. If it was comparable to a class two hurricane earlier, now it must be a class five hurricane, or more. Magnus is strong, he’s one of the strongest warlocks, being the son of a greater demon. But this is nephilim blood he’s dealing with. In power, it's unmatched by everything in this realm, including Warlock magic. Even Magnus can’t contain this kind of powerful, bloodthirsty ritual magic for long.

He summons the book, quickly recites the last closing line of the ritual and the ritual magic disperses, in every direction, off to cleanse the children. 

Magnus rolls off Alec, and sits on the ground a few feet away, gasping for air. 

It’s done. 

The mysterious illness has been dealt with. 

Magnus’s relationship with Alec is over, and so is his life. 

Any minute now, Alec will scramble up, grab his seraph blade and march Magnus straight to the institute for punishment. 

There’s a ping from his phone, and a quickly following one from Alec’s a few feet away. Magnus glances at his phone. The message is from Catarina. She reports that the children have been miraculously cured, to the delight and confusion of the Warlock Healers. She says doesn’t know how Magnus and Alec did it, but she’s eternally grateful. 

Magnus sets the phone down and muffles a sob with his hand as tears pour down his cheeks. 

It worked. He’s relieved.

The children are saved.

To his side, Magnus faintly hears ruffling as Alec’s shoes scrap on the floor as he moves. 

Alec stands up, and for the first time, Magnus is _afraid_ of Alec, what Alec will do. Alec is tall, strong, and a talented shadowhunter. Shadowhunters haven't gained their reputation from nothing - Magnus knows, he's seen himself how deadly Alec can be with his blades and his arrows.

Magnus is well aware that his actions have broken the Claves most important laws, that he's violated Alec's trust in one of the worst possible ways. He knows that there will definitely be consequences. Magnus knows his relationship with Alec - that's gone. Long gone. 

What remains to be seen is whether the consequence will be imprisonment for Magnus's long life, or death.

Magnus doesn’t dare look. He knows it’s selfish of him, but he doesn’t want to see the look of anger, betrayal, fury and hatred on Alec’s face. He knows he deserves it; he betrayed Alec in the worst way possible, but he’s selfish. He loves Alec, and he loved their relationship. He had been happy; they had been happy together. 

Magnus knows he won’t be alive much longer - or at the least, he won’t be free much longer, and he wants to remember Alec from before. The Alec who loved him unconditionally, the Alec that trusted him unconditionally, the Alec who had walked into Edom to get Magnus back, unhindered by the fact that he couldn’t actually survive in Edom.

Magnus hears footsteps come up behind him, and he trembles, tears still slipping from his eyes. There’s a ruffle of clothing, and then a hand - Alec’s hand lands on his shoulder. He can’t help it - he flinches. Alec removes his hand.

“Magnus.” Alec calls out. It takes Magnus a moment before he realizes that Alec’s voice - while trembling - isn’t angry, or furious. “Magnus, can you look at me?” 

Slowly Magnus turns his head, and looks up at Alec, his eyes still red and wet.

Alec looks back at him, and Magnus can’t read his expression. He’s still slightly shaking, but there’s none of the predicted angry, fury and hatred. 

“I- I just got a text from Catarina.” Alec starts, stumbling over his words. “The ritual that you - that we just did. That cured them?”

Magnus nods. “It’s an ancient cleansing ritual, only to be used as a last resort. Once performed it removes all illnesses from the target victims in the city.” 

“And - and you needed my blood. Nephilim blood.” Alec clarifies, his voice growing steadier.

Magnus nods again, not looking Alec in the eye. He recites. “The ritual needed nephilim blood, it’s the only substance in his realm powerful enough to sustain such a wide spread ritual. It needed 7 drops of nephilim blood willingly given, and 7 drops of nephilim blood forcibly taken. The stipulations were that the blood had to be given unknowingly. The reason for the ritual cannot be explained beforehand, and all 14 drops of blood must be taken from the same nephilim.” 

Alec is silent. Soundlessly, Alec sinks down onto the floor. Magnus doesn’t know what to make of it.

He continues. "I know it's against the law to take Nephilim blood, far less to use it," Magnus' voice shakes. "But Madzie needed it, all the children did, and - and I accept whatever repercussions, whatever punishment you see fit." 

Alec’s eyes snap to his face. ‘No.” 

Magnus's heart thumps wildly in his chest as he risks a glance at Alec. “No?” 

Alec shakes his head. “I don’t like it - but I get it. We needed to help the children, and we were running out of time. I know - we both know this was the only way. There won’t be any _repercussions_ or _punishment_ from the Clave.” 

What?

Magnus hears the words, but together… they don’t make any sense.

Magnus just broke the most upheld Shadowhunter law. He committed their highest taboo, and was ready to die for it.

But Alec is telling him that there won’t be any repercussions or punishment?

Magnus stares at Alec in confusion and shock. 

Alec takes Magnus’s hand. This time, Magnus doesn’t flinch. Alec gives him a light smile. “You saved the children Magnus. You’re - I’m not going to let anything happen to you. You’re my husband, Magnus, and I love you. I trust you. And yea, you did scare me with - with that ritual, and we definitely need to talk about that.” Alec squeezes Magnus’s hand. “But you’re still my husband, for better or for worse.” 

It finally sinks in. Magnus isn’t going to die. He’s not going to be imprisoned by the Clave, but most of all - he still has Alec. A _lec didn’t leave him, Alec doesn’t hate him._

The little composure he has left crumples, and tears of relief drip down his eyes. Alec wraps his arms around him, and rubs his back and kisses his forehead reassuringly. Magnus holds on as tightly as he can to Alec. Because even now, after dating for months and being married for several more, Alec’s love for him continues to surprise him and break through all of his fears and expectations. 

Eventually, Magnus relaxes. He knows that the conversation they need to have isn’t going to be pleasant in the slightest, but he knows that Alec isn’t leaving him.

No matter what’s said or what happens, Magnus knows it’ll be okay; he has Alec.

The End.

**Author's Note:**

> I hope everyone's staying safe and healthy during these troubling times.  
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>   
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> 😭 = the angst got to you  
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